<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<style>
    button{height:50px;width:200px;}
    video{height:300px;margin:50px;display: block;}
</style>

<body>
    <video class="play" src="https://resource-1252108727.cos.ap-guangzhou.myqcloud.com/gxkt/video/1539583561997.mp3"
        controls></video>
    <audio class="play" src="http://resource-1252108727.file.myqcloud.com/gxkt/video/1536816842222.mp3" controls style="display:none;"></audio>

    <button id="play" type="button">开始播放</button>
</body>
<script>
    var klass = document.getElementsByClassName('play');
    var play_btn = document.getElementById('play');
    play_btn.onclick = function () {
        for (var n = 0; n < klass.length; n++) {
            klass[n].play();
        }
    }

</script>

</html>